Note that the last part of the Ant targets javaWebStart, applet and viewer requires a passphrase for keystore to sign the deployed jars. For security reasons, the required file keys.keytool isn't provided with this source code. You'll have first to generate this file and choose a passphrase, with the following command run in the directory where you uncompressed this archive:
keytool -genkey -keystore keys.keytool -alias SweetHome3D